Data Communication

Question 1

The process of transferring digital information (data) between two or more points

Answer 1

Data Communications

Question 2

Defined as information that has been processed

Answer 2

Data

Question 3

It is referring to knowledge or intelligence

Answer 3

Information

Question 4

It a standards body under ITU. It is the primary organization for developing standards on telephone and data communications systems among participating governments

Answer 4

Comite Consultatif International Telegraphique or

Consultative Committee on International Telegraphy and Telephony (CCITT)

Question 5

Group of the CCITT that addresses the regulatory aspects of international communications including telegraph operations, telex service, tariffs, public networks and many aspects o telephony

Answer 5

Study Group A

Question 6

Group of the CCITT that concentrates its efforts on telegraph transmission, equipment specifications and telegraph signaling

Answer 6

Study Group B

Question 7

Group of CCITT that studies international telephone operations

Answer 7

Study Group C

Question 8

Group of CCITT that addresses problems relating to international data transmission service and international data networks

Answer 8

Study Group D

Question 9

A voluntary organization consisting of national standards committees of each member country

Answer 9

International Standards Organization (ISO)

Question 10

A voluntary standards body in the US and is a member of the ISO

Answer 10

American National Standards Institute (ANSI)

Question 11

A national trade association which is very influential in developing standards in North American Countries

Answer 11

Electronic Industries Association (EIA)

Question 12

A US professional organization of electrical, electronics and computer engineers

Answer 12

Institute of Electrical and Electronics Engineering (IEEE)

Question 13

Type of Connection Combination used in data communication system

Answer 13

DTE and DCE combination

Question 14

A general term that describes the interface equipment used at the stations to adapt the digital signals from the computers and terminals to a format more suitable for transmission

Answer 14

Data Terminal Equipment (DTE)

Question 15

A terminal that is old form of DTE that was invented to replace the Morse telegrapher

Answer 15

Teleprinter

Question 16

A terminal that is known as video displace terminal (VDT) was developed as an alternative to teleprinter terminals

Answer 16

Cathode Ray Tube (CRT) Terminal

Question 17

Classifications of CRT terminal that are teletype compatible and offer a limited number of functions

Answer 17

Dumb Terminals

Question 18

Classifications of CRT terminal that offer enhanced functions such as editing and formatted data entry

Answer 18

Smart Terminals

Question 19

Classifications of CRT terminal that feature software support

Answer 19

Intelligent or user-programmable terminals

Question 20

A terminal that replaces most teleprinters and CRT terminals as the terminal of choice as a standard terminal

Answer 20

PC Terminal

Question 21

A general term that describes the equipment that converts digital signals to analog signals and interfaces the data terminal equipment to analog transmission medium

Answer 21

Data Communications Equipment (DCE)

Question 22

A facility that connects two points together

Answer 22

Transmission Channel

Question 23

It identifies how various stations within the network are interconnected

Answer 23

Topology

Question 24

Types of Network Topology

Answer 24

Ring
Mesh
Star
Line
Tree
Bus
Fully Connected

Question 25

A network topology could be configured for traffic to flow in one direction or in both directions

Answer 25

Ring Topology

Question 26

A network topology that every node in the network is connected to each other by transmission facilities

Answer 26

Mesh Topology

Question 27

A network topology that is very economical when traffic relations are comparatively low but inefficient particularly when traffic intensities grow

Answer 27

Star Topology

Question 28

It is so called the full mesh topology

Answer 28

Fully Connected Topology

Question 29

A network topology that there is a common line to which several nodes can connect

Answer 29

Bus Topology

Question 30

A network topology that is an extension of the bus structure with branches

Answer 30

Tree Topology

Question 31

Two Configurations of Data Communications Networks

Answer 31

Point-to-point | Multipoint

Question 32

A circuit connection considered most elemental in data connectivity

Answer 32

Point-to-point

Question 33

A circuit connection that the main station is commonly a CPU and the outstations are workstations

Answer 33

Multipoint

Question 34

Four Transmission Modes in Data Communications

Answer 34

Simplex Half-duplex Full-duplex Full/Full Duplex

Question 35

Type of data transmission that transmits one way only (unidirectional)

Answer 35

Simplex Mode

Question 36

Type of data transmission that transmits in both directions but not simultaneous

Answer 36

Half-duplex Mode

Question 37

Type of data transmission that transmits in both directions simultaneously but only between two statios

Answer 37

Full-duplex Mode

Question 38

Type of data transmission that transmits in both directions simultaneously between several stations

Answer 38

Full/Full-duplex Mode

Question 39

Three types of Switching Concepts

Answer 39

Circuit Switching Message Switching Packet Switching

Question 40

A type of switching used for making a standard telephone call on the public telephone network

Answer 40

Circuit Switching

Question 41

A type of switching that follows "store-and-forward" switching which the data including source and destination identification codes are transmitted into the network and stored in a switch

Answer 41

Message Switching

Question 42

A type of switching that follows "hold-and-forward" switching which the data is divided into smaller segments called packets prior to transmission through the network

Answer 42

Packet Switching

Question 43

Three common codes used in data communications

Answer 43

Baudot Code American Standard Code for Information Interchange (ASCII) Extended Binary-Coded Decimal Interchange Code (EBCDIC)

Question 44

It is a 5-bit character code used primarily for low-speed teletype equipments

Answer 44

Baudot Code

Question 45

This code is adopted in the US in 1963 to standardize data communications code in America. It contains 7 bits in a character equivalent to 128 code combinations

Answer 45

ASCII Code

Question 46

This code is the true 8-bit character code developed by IBM

Answer 46

EBCDIC Code

Question 47

Two important aspects in data transmission error control

Answer 47

Detection | Correction

Question 48

The process of monitoring the received data and determining when a transmission error has occured

Answer 48

Error Detection

Question 49

Type of Error Detection Schemes

Answer 49

``` Redundancy Exact-Count Encoding Parity Vertical Redundancy Checking (VRC) Horizontal or Longitudinal Redundancy Checking (HRC or LRC) Cyclic Redundancy Check (CRC) ```

Question 50

It involves transmitting each character twice if the same character is not received twice in succession, a transmission error has occured

Answer 50

Redundancy

Question 51

The number of 1's in each character is the same to determine if a transmission error has occured

Answer 51

Exact-Count Encoding

Question 52

The simplest error detection scheme used in data communications systems and is used in both vertical and horizontal redundancy checking

Answer 52

Parity

Question 53

Two modes of Parity error detection

Answer 53

Odd Parity | Even Parity

Question 54

An error detection scheme that uses parity to determine if a transmission error has occurred within a character (Character Parity)

Answer 54

Vertical Redundancy Checking (VRC)

Question 55

An error detection scheme that uses a parity to determine if a transmission error has occurred in a message (Message Parity)

Answer 55

Horizontal or Longitudinal Redundancy Checking (HRC or LRC)

Question 56

The most reliable scheme for error detection capable of detecting 99.95% of all transmission errors

Answer 56

Cyclic Redundancy Checking (CRC)

Question 57

Type of Error Correction Schemes

Answer 57

Symbol Substitution Re-transmission Forward Error Correction (FEC)

Question 58

It is designed to be used in a human environment

Answer 58

Symbol Substitution

Question 59

It is often called "ARQ" or automatic request for re-transmission

Answer 59

Re-transmission

Question 60

The only error correction scheme that actually detects and corrects transmission errors at the receive end without calling for re-transmission

Answer 60

Forward Error Correction

Question 61

A popular FEC code was developed by R. W. Hamming

Answer 61

Hamming Code

Question 62

Formula for Hamming Code

Answer 62

2ⁿ ≥ m + n +1 n = number of Hamming Bits m = number of bits in the data character

Question 63

The operation or activity of two or more things at the same time or rate

Answer 63

Synchronization

Question 64

Common types of synchronization techniques

Answer 64

Bit or Clock Synchronization | Character Synchronization

Question 65

Synchronization that is achieved through a receive clock signal which is coincident with the received serial data stream

Answer 65

Bit or Clock Synchronization

Question 66

Synchronization that is accomplished by recognizing one or two phasing characters often called SYN or sync characters

Answer 66

Character Synchronization

Question 67

A start-stop transmission that each data is framed between a start and stop bits

Answer 67

Asynchronous Transmission

Question 68

Formula for h-factor of an FSK modulator of Asynchronous modem

Answer 68

``` h= | fₘ - fₛ | / fb fₘ = mark (logic 1) frequency (Hz) fₛ = space (logic 0) frequency (Hz) fb = input bit rate (bps) ```

Question 69

A unique synchronizing character called the SYN characters is transmistted at the beginning of the message

Answer 69

Synchronous Transmission

Question 70

SYN characters are inserted in the transmitted data stream to ensure character synchronization throughout the message

Answer 70

Message Synchronization